Overtaking Stationary and Moving Obstacles for Autonomous Ground Vehicles

2006 ◽  
Author(s):  
Ghasem Amini Javid ◽  
Mohammad Durali ◽  
Alireza Kasaaizadeh
Keyword(s):  
Sliding Mode ◽  
Control Strategies ◽  
Decision Criterion ◽  
Design Tool ◽  
Lateral Acceleration ◽  
Lateral Motion ◽  
Motion Controller ◽  
Test Environment ◽  
Virtual Test ◽  
Moving Obstacles

In this paper, a method for overtaking stationary and moving obstacles will be introduced. The method consists of designing a desired trajectory for lateral motion of the vehicle and then using a lateral motion controller for tracking this desired trajectory. The desired trajectory is a sigmoid exponential function of relative distance between the vehicle and the obstacle and guarantees overtaking the obstacle, if tracked exactly, despite of lateral and longitudinal motions of the obstacle. Lateral acceleration of the vehicle should not exceed safety limits during tracking desired trajectory. This matter has been used as a decision criterion for determining feasible and unfeasible desired trajectories. A neural network has been trained for predicting maximum lateral acceleration (MLA) during overtaking maneuver. The lateral motion controller is a sliding mode controller which has been designed to be robust to uncertainties existing in lateral dynamic model of the vehicle. A virtual test environment has been developed as a design tool for developing new control strategies for autonomous vehicles. The lateral controller has been tested extensively using this virtual test environment and has shown satisfactory performance in controlling the vehicle, even in existence of noises and disturbances.

Nonlinear Active Rollover Prevention Control Strategies for a 5-Axle Tractor/Semitrailer

2001 ◽  
Author(s):  
A. Scott Lewis ◽  
Moustafa El-Gindy
Keyword(s):  
Active Control ◽  
Load Transfer ◽  
Sliding Mode ◽  
Control Strategies ◽  
Lateral Load ◽  
Lateral Acceleration ◽  
Computer Simulation Model ◽  
Parameter Uncertainties ◽  
Transfer Ratio ◽  
Vehicle Rollover

Abstract This paper presents new active control strategies to prevent heavy vehicle rollover and focuses mainly on cases of maneuver-induced rollover such as rollover in cornering and lane-change maneuvers. Two performance measures as control strategies are explored: the lateral load transfer ratio and the trailer lateral acceleration. A nonlinear 75,000 pound 5-axle tractor/semitrailer computer simulation model has been used to demonstrate the effectiveness of the proposed active control system. A new non-linear sliding mode controller has been designed and found to be effective in improving the dynamic performance and roll stability, regardless of parameter uncertainties, such as tires or suspension characteristics. The controller torque requirement is limited by the differential dynamic braking forces that the tractor drive axles are able to produce as a function of the applied dynamic loads and road surface condition. The results show that with this new controller, the vehicle lateral acceleration can be controlled to prevent rollover without significant change of the vehicle trajectory when active yaw torque is applied to the tractor drive axles. Also, simulation results indicate that the vehicle rollover might be prevented using either the lateral load transfer ratio or the lateral acceleration at the trailer centre of gravity as control strategies.

Lateral obstacle avoidance control based on driving behavior recognition of the preceding vehicles in adjacent lanes

2020 ◽  
Vol 68 (10) ◽  
pp. 880-892
Author(s):  
Youguo He ◽  
Xing Gong ◽  
Chaochun Yuan ◽  
Jie Shen ◽  
Yingkui Du
Keyword(s):  
Obstacle Avoidance ◽  
Lateral Displacement ◽  
Longitudinal Velocity ◽  
Driving Behavior ◽  
Lateral Acceleration ◽  
Lateral Motion ◽  
Behavior Recognition ◽  
Dynamic Surface ◽  
Lane Changing ◽  
The Impact

AbstractThis paper proposes a lateral lane change obstacle avoidance constraint control simulation algorithm based on the driving behavior recognition of the preceding vehicles in adjacent lanes. Firstly, the driving behavior of the preceding vehicles is recognized based on the Hidden Markov Model, this research uses longitudinal velocity, lateral displacement and lateral velocity as the optimal observation signals to recognize the driving behaviors including lane-keeping, left-lane-changing or right-lane-changing; Secondly, through the simulation of the dangerous cutting-in behavior of the preceding vehicles in adjacent lanes, this paper calculates the ideal front wheel steering angle according to the designed lateral acceleration in the process of obstacle avoidance, designs the vehicle lateral motion controller by combining the backstepping and Dynamic Surface Control, and the safety boundary of the lateral motion is constrained based on the Barrier Lyapunov Function; Finally, simulation model is built, and the simulation results show that the designed controller has good performance. This active safety technology effectively reduces the impact on the autonomous vehicle safety when the preceding vehicle suddenly cuts into the lane.

scholarly journals Zero-Width Quasi-Sliding Mode Band in the Presence of Non-Matched Uncertainties

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3011
Author(s):  
Paweł Latosiński ◽  
Andrzej Bartoszewicz
Keyword(s):  
Sliding Mode Control ◽  
Discrete Time ◽  
Sliding Mode ◽  
Control Strategies ◽  
Relative Degree ◽  
Band Width ◽  
Representative Point ◽  
Mode Control ◽  
Sliding Motion ◽  
Selection Of

Sliding mode control strategies are well known for ensuring robustness of the system with respect to disturbance and model uncertainties. For continuous-time plants, they achieve this property by confining the system state to a particular hyperplane in the state space. Contrary to this, discrete-time sliding mode control (DSMC) strategies only drive the system representative point to a certain vicinity of that hyperplane. In established literature on DSMC, the width of this vicinity has always been strictly greater than zero in the presence of uncertainties. Thus, ideal sliding motion was considered impossible for discrete-time systems. In this paper, a new approach to DSMC design is presented with the aim of driving the system representative point exactly onto the sliding hyperplane even in the presence of uncertainties. As a result, the quasi-sliding mode band width is effectively reduced to zero and ideal discrete-time sliding motion is ensured. This is achieved with the proper selection of the sliding hyperplane, using the unique properties of relative degree two sliding variables. It is further demonstrated that, even in cases where selection of a relative degree two sliding variable is impossible, one can use the proposed technique to significantly reduce the quasi-sliding mode band width.

Comprehensive Analysis for Influence of Controllable Damper Time Delay on Semi-Active Suspension Control Strategies

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Yechen Qin ◽  
Feng Zhao ◽  
Zhenfeng Wang ◽  
Liang Gu ◽  
Mingming Dong
Keyword(s):  
Time Delay ◽  
Dynamic Characteristics ◽  
Ride Comfort ◽  
Hybrid Control ◽  
Sliding Mode ◽  
Control Strategies ◽  
Active Suspension ◽  
Test System ◽  
Suspension Control ◽  
Simulation Results

This paper presents a comprehensive comparison and analysis for the effect of time delay on the five most representative semi-active suspension control strategies, and refers to four unsolved problems related to semi-active suspension performance and delay mechanism that existed. Dynamic characteristics of a commercially available continuous damping control (CDC) damper were first studied, and a material test system (MTS) load frame was used to depict the velocity-force map for a CDC damper. Both inverse and boundary models were developed to determine dynamic characteristics of the damper. In addition, in order for an improper damper delay of the form t+τ to be corrected, a delay mechanism of controllable damper was discussed in detail. Numerical simulation for five control strategies, i.e., modified skyhook control SC, hybrid control (HC), COC, model reference sliding mode control (MRSMC), and integrated error neuro control (IENC), with three different time delays: 5 ms, 10 ms, and 15 ms was performed. Simulation results displayed that by changing control weights/variables, performance of all five control strategies varied from being ride comfort oriented to being road handling oriented. Furthermore, increase in delay time resulted in deterioration of both ride comfort and road handling. Specifically, ride comfort was affected more than road handling. The answers to all four questions were finally provided according to simulation results.

scholarly journals Dynamic Analysis and Control of an Automatic Transmission for Start-Stop Function and Efficiency Improvement

2015 ◽  
Vol 2015 ◽  
pp. 1-13
Author(s):  
Yang Liu ◽  
Shuhan Wang ◽  
Peng Dong ◽  
Xiangyang Xu
Keyword(s):  
Control Strategies ◽  
Automatic Transmission ◽  
Simulation Method ◽  
Transmission Efficiency ◽  
The Novel ◽  
Test Results ◽  
Test Environment ◽  
Pump System ◽  
Oil Pump ◽  
And Control

An electric oil pump (EOP) was integrated into the hydraulic system and an automatic transmission (AT) mechanical oil pump (MOP) was downsized. These processes were performed to combine a start-stop function with the AT and further improve the transmission efficiency. Furthermore, this study established a dynamics model of power loss and leakage of an 8-speed AT; a flow-based control algorithm of the EOP was then developed to realize the start-stop function and support the MOP to meet the flow requirement of the system. Based on a driving simulation method, sizes of the MOP and EOP that ensured optimal fuel economy were selected. A control strategy for the starting clutch was also developed to minimize the starting delay of the test vehicle. A test environment on a rig and prototype vehicle was established to verify the feasibility of the proposed control strategies. The test results indicated that the transmission functioned favorably with the novel two-pump system presented, and a quick and smooth starting performance was achieved when the engine was restarted. The findings in this study are extremely valuable for forward designs of an AT for realizing start-stop function and improving efficiency.

Development of a Laboratory Equipment for Dynamic Systems and Process Control Education

2014 ◽  
Author(s):  
Rafael E. Vásquez ◽  
Norha L. Posada ◽  
Fabio Castrillón ◽  
David Giraldo
Keyword(s):  
Process Control ◽  
Dynamic Systems ◽  
Sliding Mode ◽  
Control Strategies ◽  
Academic Research ◽  
Nonlinear Behavior ◽  
Industrial Training ◽  
Laboratory Equipment ◽  
Dynamic Matrix ◽  
Control Education

This paper addresses the development of an equipment to teach control engineering fundamentals. The design requirements were determined by users that perform academic, research and industrial training tasks in the area of dynamic systems and process control. Such requirements include: industrial instrumentation; measurement of controlled and manipulated variables, and disturbances; process reconfigurability; different control technologies; several control strategies; appropriate materials for visualization; and compact shape to optimize lab space. The selected process is a tank system that allows one to choose among several dynamic behaviors: first, second, and third order, linear and nonlinear behavior, and dead time; the mathematical model that represents the dynamics of the system is presented. A traditional 3-stage design methodology that includes conceptual, basic and detailed design was followed. The developed equipment allows the user to select from three different technological alternatives to control the system: a PLC, an industrial controller, and a computer. With such flexibility, several control strategies can be implemented: feedback, feedforward, PID, LQG, nonlinear control (gain scheduling, sliding mode, etc.), fuzzy logic, neural networks, dynamic matrix control, etc. The developed system is being used to teach undergrad courses, grad courses, and industrial training. Additionally, the equipment is useful in research projects where grad students and researches can implement and test several advanced control techniques.

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